Stabilizing dreams is a pain in the butt, I noticed if I try to do something too off the wall it starts to make the dreams unstable. So try focusing on something like your hands or feet you know what they look like and they may give you a base to solidify the rest of the dream. Reading itself and trying to do mathematics and the same ilk of things tend to be unstable in dreams for most people.

I think it has to do with those tasks being very logic oriented/pattern using. and therefor left brained.

The right side of your brain is the abstract, musical, creative, pattern seeker and also supposedly the part of the brain invoved with dreaming. So I think numbers and letters tend to get jumbled and makes reading difficult...

It may have to do with the dominance of your brain halves possibly if your more left brain dominant you will have an easier time reading if your right brain dominant it may make it more difficult. If your ambidexterous you may have a better chance of it, but thats speculation

I can read in my dreams, but I dont know how I do it =/ but then again my dreams are weird.

But if you notice things becoming unstable try looking at your hands and or feet and focus on them like I said, it takes time, but you will eventualy be able to stabilize your dreams and read, a friend of mine worked on it for a while and she was able to read and write.

Good luck